When watching TV the intent is to watch TV, not purchase soap, a car, or a soft drink. It might be that Facebook's ads are simply the wrong type/style for the kind of interaction people use it for. It does seem like Facebook ads feel like Google search ads.
Or, TV ads don't actually work very well. Since we can't track conversions, we don't really know. Advertisers are paying for it, so why rain on the parade?
